Anthracyclines form one of the largest families of naturally occurring bioactive compounds. Several members of this family have shown to be clinically effective anti-neoplastic agents. These include, for example, daunorubicin, doxorubicin, idarubicin, epirubicin, pirarubicin, zorubicin, aclarubicin, and carminomycin. For instance, these compounds have shown to be useful in bone marrow transplants, stem cell transplantation, treatment of breast carcinoma, acute lymphocytic and non-lymphocytic leukemia, chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and other solid cancerous tumors.
U.S. Pat. Nos. 4,112,076, 4,345,068, 4,861,870, 5,945,518, and 5,874,550 disclose the preparation of epirubicin hydrochloride and its usage as an anticancer agent, which is represented by the formula:

Currently, there are two major methods of extraction of epirubicin hydrochloride from solutions. The first method involves the treatment of the organic solution of epirubicin base with a solution of hydrogen chloride in methanol. See e.g., U.S. Pat. No. 4,112,076. Alternatively, the second method involves the precipitation of epirubicin hydrochloride from an aqueous or organo-aqueous solution with the aid of acetone. See e.g., U.S. Pat. No. 4,861,870.
U.S. Pat. No. 6,087,340 discloses an injectable ready-to-use solution containing epirubicin hydrochloride. More specifically, the '340 patent discloses a stable, injectable, sterile, pyrogen-free, anthracycline glycoside solution which consists essentially of a physiologically acceptable salt of an anthracycline glycoside dissolved in a physiologically acceptable solvent therefore, which has not been reconstituted from a lyophilizate, which has a pH of from 2.5 to 3.5 and which is preferably contained in a sealed glass container. While the '340 patent discloses injectable, ready-to-use preparations, the '340 patent does not disclose the stabilization of epirubicin hydrochloride itself as a bulk drug.
U.S. Pat. No. 6,376,469 discloses a β-Type form of crystalline amrubicin hydrochloride having improved thermal stability.
It is desirable to have a crystalline form of epirubicin hydrochloride which has improved thermal stability characteristics. Variation of thermal stability for different crystalline forms of epirubicin hydrochloride is described for the first time herein.